Once everything was reassembled, he hooked it up to his computer and gave it a spin – success!

While he is happy with how the phone works at the moment, he already has plans for improving it. He is currently looking for a way to use the handset hook to disconnect calls as well as a way to implement the rotary dial for number entry. We think that hacking a Bluetooth headset would easily take care of the first part, as well as eliminate the need for any sort of wired interface to his PC. It would also make it dead simple to use with any other Bluetooth-enabled device such as a cell phone.

We’re pretty sure he is open to implementation suggestions, so let us know what you think.

Post navigation

30 thoughts on “Hacking Analog Phones For VOIP”

I, too, have a 500 set hooked up to make voip calls through google voice. A SIP or IAX ATA that supports pulse dial, and a relatively recent version on asterisks makes it work just about like it did when it was connected to a line provided by the phone company. I picked up an Innomedia MTA6328-2Re on ebay for ~$12 and never looked back.

-The most elegant solution would be a composite USB device. I think that’s too much work.
-Audio is essentially taken care of.
-Getting the hangup and dialing to work without Asterisk would likely require a custom application running in the background, a custom driver, or both.
-Or you could make the numbers a numeric keypad, and leave hangup alone, but this wouldn’t be a seamless solution.

A nice hack. While the hand set on these older phones are much easier to use than contemporary phones/hands sets, one would still have to hold it against your shoulder to still use the keyboard. Things like that, and men sitting on fat wallets all day fills out chiropractor’s daily schedule. While it certainly would be more expensive than a 3.99 thrift store purchase. and junk box parts, I’d suggest making a true communications headset for multitasking. Like what radio operators or call center operators use. Me if such a phone still worked I plug it into my POTS. Somewhere around here I still should have a functional trim line pulse dial phone if not two. Ma Bell didn’t demand them back after the break up, and neither billed me for them. That or the old SWB charge me so little, I don’t recall the cost.

So all you did was splice two wires together? You should check out the link in the above comments to see how to really mod the phone. In that mod they actually add components and functionality to the phone. How do you plan on interfacing with the Google voice app if you only added a headphone cable to the hand set?

Sparkfun had the right idea, but the Bluetooth phone they sell doesn’t work well and even they admit it.
Of course, they don’t tell you that until after you purchase it, but its pretty much defective by design and they know it.

If someone could actually make a Bluetooth one that worked, it would be a happy day indeed!

Generally, I wouldn’t call wiring a speaker and mic to existing hardware a hack.

Then again, if you can get the rotary pulses to translate into dtmf or serial signals, this will be a masterpiece.

I remember reading an article about a guy using an old school non-digital modem (complete with acoustic coupling device since Ma Bell had some strict rules back then) to interface with the internet on modern hardware.

If anyone can get an old school teletype machine on the internet with minimal usage of modern hardware… now that’s a hacker. :P

Yes, this is not much of a hack. It’s really just step one in a process of many steps which I am still in the planning stages of. I bought the phone, and did this within 2 hours. I’ve only had it for 24 hours now, and I’m simply expanding my knowledge base about these phones before I do anything further, primarily because I want to do as little damage as possible to the original guts of the phone.

yes, you could buy one of the modern ones or set it up through an ATA, but really this was about the challenge of the thing itself, not just the solution.

My future plans involve a. better cabling system, making use of the actual RJ jack on the back, b. and arduino to translate the pulse dial into actual signal that can be used as essentially ‘quick dials,’ and somehow getting the bells set up. Then, yes, it’ll be a solid hack. :D This is just my first step.

If he’s going to consider decoding numbers to run stuff, he should make a visual radial menu on screen (usually used with number pads, and sometimes in games).

@Dave
Technically it’s a hack because it requires them to use a device in a non-standard way and to modify it. Granted it’s a fairly simple one

It looks like some of the early modems were literally dumber than dirt, all they did was modulate the signal sent to them and received, without doing handling, error correction, or anything else at all (the user even had to manually call and hangup).By that measure. they are actually REAL modems, not smart devices.

The internet case is significantly helped by the fact that that guy was more or less dialing to access a system and running a web browser remotely. That’s not too hard because of the prevalence of dial-up internet and modem standardization early on.

What would be a real hack, and likely impossible would be to enable calling or answering multiple phones simultaneously with the same modem by fudging some of the signals to a phone and the computer.

I’ve got a Western Electric 1D2 pay phone. I have a future project to create a device that precisely emulate central office functions. But in the meantime I think I’ve come up with a hack.

There’s a chip on the 32A frame that generates the beep tones but I suspect it does more. I’ve got to do some circuit tracing but I think I can get the coin values off it. I can mount an LCD above and use it as a piggy bank in the interim.

This hack is much nicer and works pretty well with Bluetooth. I am amazed by all the features it has including rotary dial, redial, voice recognition dial, text message notification, inward dialing using DTMF, speed dial and more. http://www.sqnewton.com

@Dave – “I remember reading an article about a guy using an old school non-digital modem (complete with acoustic coupling device” : What is a non-digital modem? How does it interface with a computer if there’s no digital part?

Just stick a small cheap VoIP ATA in it and replace the cord with an Ethernet cable. Heck if you don’t want to hack the phone at all, just plug it into an external ATA box, you don’t even need the computer any more!

Yes, there are better solutions out there, but I’m not paying $100+ for a bluetooth phone. I wanted to make this myself, without spending money.

Same for the VoIP atas, I’m not interested in spending money on that sort of thing.

To some of the others: I’m not sure what you mean “pretend telephony.”
I’m not inserting pretend telephony into anything. I’m modifying the telephony that already exists to work with a totally different purpose in mind.

Sure, the push button phones are easier to hack so the buttons work, but thats because they operate on an entirely different principle, and are much easier to adapt to modern use. Pulse dial phones are much more antiquated, and the translation is much more difficult.

A “non-digital” modem is just like it sounds…an analog modem actually anything that isn’t an analog modem(modulator/demodulator) isn’t a modem it’s an adapter. The interface could be as simple as plugging in to the mic and line in jacks but that was harder to interface with the software so it was done with the serial interface…but it is still analog communications. I followed the link for the rotatone and that device looks cool but the “pre-made” phones are insanely priced.

I think this is a great first step to an awesome hack. Been using google voice myself exclusively for months now (not for any great experiment, but because I am broke and my neighbor doesn’t secure his wi-fi- free phone can’t be beat). I hacked an older phone for a voip solution several years ago, and although it’s not a huge accomplishment, it’s definitely reminded me that I still have that phone somewhere, and could use it now.sometimes this simple stuff is interesting, and is a step toward a more complex hack. I like it.

Use a Grandstream HT502 ATA and a Netgear WNCE2001 WLAN-to-RJ45 Adapter. Your vintage phone with rotary dial will function properly with any SIP provider. The only wire needed is to power the two aforementioned high tech devices.